package com.hmdp.service.impl;

import com.hmdp.dto.Result;
import com.hmdp.entity.SeckillVoucher;
import com.hmdp.entity.VoucherOrder;
import com.hmdp.mapper.VoucherOrderMapper;
import com.hmdp.service.IVoucherOrderService;
import com.baomidou.mybatisplus.extension.service.impl.ServiceImpl;
import com.hmdp.utils.RedisIdWorker;
import com.hmdp.utils.SimpleRedisLock;
import com.hmdp.utils.UserHolder;
import org.redisson.api.RLock;
import org.redisson.api.RedissonClient;
import org.springframework.aop.framework.AopContext;
import org.springframework.data.redis.core.StringRedisTemplate;
import org.springframework.stereotype.Service;
import org.springframework.transaction.annotation.Transactional;

import javax.annotation.Resource;
import java.time.LocalDateTime;

/**
 * <p>
 *  服务实现类
 * </p>
 *
 * @author 虎哥
 * @since 2021-12-22
 */
@Service
public class VoucherOrderServiceImpl extends ServiceImpl<VoucherOrderMapper, VoucherOrder> implements IVoucherOrderService {


    @Resource
    SeckillVoucherServiceImpl seckillVoucherService;


    //分布式主键生成器
    @Resource
    RedisIdWorker redisIdWorker;

    @Resource
    StringRedisTemplate stringRedisTemplate;

    @Resource
    RedissonClient redissonClient;

    @Override
    public Result seckillVoucher(Long voucherId) {
        //1.查询优惠券
        SeckillVoucher voucher = seckillVoucherService.getById(voucherId);

        //2.判断秒杀是否开始
        if (voucher.getBeginTime().isAfter(LocalDateTime.now())){

            return Result.fail("秒杀尚未开始");
        }

        //3.判断秒杀是否结束1

        if (voucher.getEndTime().isBefore(LocalDateTime.now())){

            return Result.fail("秒杀已经结束");
        }

        //4.判断库存是否充足
        if (voucher.getStock() < 1){
            return Result.fail("库存不足");
        }

        //5.一人一单的实现
        Long userId =  UserHolder.getUser().getId();




        //创建锁
        //SimpleRedisLock lock = new SimpleRedisLock("order:" + userId, stringRedisTemplate);

        RLock lock = redissonClient.getLock("lock:order" + userId);

        //获取锁v 1200秒是测试用的 redisson分布式锁有三个参数 第一个最大等待时间(实现可重功能) 最大超时释放时间 时间单位

        //boolean isLock = lock.tryLock(1200);
        boolean isLock = lock.tryLock();

        if (!isLock){
            return Result.fail("一个用户只允许下一单");
        }


        try {
            //代理对象调用？？
            //获取代理对象，与事务有关的代理对象 防止没提交，就释放锁
            IVoucherOrderService proxy = (IVoucherOrderService) AopContext.currentProxy();
            return proxy.createVoucherOrder(voucherId);
        } finally {
            lock.unlock();
        }

    }

    @Override
    @Transactional
    public Result createVoucherOrder(Long voucherId){


        //5.一人一单的实现
        Long userId =  UserHolder.getUser().getId();

        //这里的toString,会创建一个新的对象出来
            //5.查询订单
            int count = query().eq("user_id", userId)
                    .eq("voucher_id", voucherId)
                    .count();

            //判断是否存在
            if (count > 0) {
                return Result.fail("用户已经购买过一次了！");
            }

            //5.扣减库存
            //相当于 sql语句 UPDATE tb_seckill_voucher SET stock = stock - 1 WHERE voucher_id =  12;
            //这里加了一段乐观锁代码。防止超卖
            //
            // set stock = stock - 1 where voucher_id = ? and stock = voucher.getStock

            boolean succeed = seckillVoucherService.update()
                    .setSql("stock = stock - 1")  //set stock = stock - 1;
                    .eq("voucher_id", voucherId).gt("stock", 0) //where id = ? and Stock >0
                    .update();

            if (!succeed) {
                return Result.fail("库存不足！");
            }

            //6.创建订单
            VoucherOrder voucherOrder = new VoucherOrder();
            //6.1 订单id
            long orderId = redisIdWorker.nextId("order");

            voucherOrder.setId(orderId);
            //6.2 用户id

            voucherOrder.setUserId(userId);
            //6.3 代金券id
            voucherOrder.setVoucherId(voucherId);
            save(voucherOrder);
            //7.返回订单id

            return Result.ok(orderId);
    }
}
